The present Invention relates to new heat-resistant high modulus materials, to compositions used for the manufacture thereof and to finished product parts which may be obtained from such materials Reaction-injection molding is a rapid polymerization process which is commonly used to produce polyurethanes and polyureas having elastomeric to rigid properties. This technology is used in the production of automobile parts, such as bumpers or fenders. In said process, two highly reactive streams of chemical compounds are intermixed under a high pressure, for example about 80 to 200 bars, in a mixing chamber having small dimensions where the streams are directly injected into each other. The mixed material Immediately runs into a mold where the chemical reaction continues and where the molded part is cross-linked. One of the streams contains a polyisocyanate, while the other flow contains a chain extender and a polymer, which has a high molecular weight and is reactive with isocyanate.
High modulus polymers obtained by the reaction-injection molding process can replace steel automobile panels, provided that they can withstand finishing operations on production lines where high temperatures prevail. A composite material is known from U.S. Pat. No. 4,880,872, which material is obtained by such a process from a first mixture of aromatic polyisocyanate and a cross-linking agent and from a second mixture comprising:
a) at least 5% by weight of an ethylenically unsaturated compound containing at least one ethylenically unsaturated monomer, such as styrene, and at least one ethylenically unsaturated polymer, such as a polyester; PA1 b) from 30 to 75% by weight of a polyoxyalkylene polyamine having a molecular weight of between 190 and 3 000, and PA1 c) from 5 to 40% by weight of a chain extender selected from the C.sub.1 -C.sub.16 aliphatic diamines, C.sub.6 -C.sub.16 cycloaliphatic diamines and aromatic diamines, having at least one alkyl substituent in the ortho position of each amine group. PA1 a component A comprising a polyfunctional isocyanate compound and a radical polymerization catalyst, and PA1 a component B comprising a mixture (i) of a solution of an ethylenically unsaturated monomer wherein are dissolved about 40 to 90% by weight of an unsaturated polyester-polyol, substantially free from water, comprising at least a dicarboxylic alkene group and having an acid number lower than 5, and (ii) a nitrogenated polyfunctional compound comprising at least two nitrogen atoms in each molecule, which, once reacted with component A, has a molecular weight sufficient for forming the first soft polyurea phase, PA1 a first mixture comprises at least one polyisocyanate and at least one catalyst for the reaction of the isocyanate functions with the ethylenically unsaturated polymer of the second mixture, and in that PA1 the second mixture comprises, per 100 parts by mass: PA1 at least one cross-linking accelerator, PA1 at least one powdery filler, PA1 at least one fibrous reinforcing filler. PA1 A and Y are selected from the alkyl groups having 1 to 10 carbon atoms, PA1 n is a number between 2 and 70, PA1 b is a number between 8 and 90, PA1 a and c are numbers such that their sum total is between 1 and 4, PA1 x, y and z are numbers between 2 and 40. PA1 (a) tertiary amines such as bis (dimethyl amino ethyl) ether, trimethyl amine, triethyl amine, N-methyl morpholine, N-ethyl morpholine. N,N-dimethyl benzylamine, N,N-dimethyl ethanol amine, N,N,N',N'-tetramethyl-1,3-butane diamine, triethylanol amine, 1,4diazabicyclo[2.2.2.]octane and pyridine oxide, PA1 (b) tertiary phosphines such as trialkyl phosphines and dialkyl benzyl phosphines, PA1 (c) strong bases such as the hydroxides, alcoholates and phenolates of alkali metals and alkaline earth metals. PA1 (d) metal salts of strong acids such as ferric chloride: stannic chloride, stannous chloride and bismuth chloride, antimony trichloride and bismuth nitrate, PA1 (d) chelates, such as those which can be obtained from acetyl acetone, benzoyl acetone, trifluoroacetyl acetone, ethyl acetoacetate, salicylaidehyde, cyclopentanone-2-carboxylate, acetyl acetoimine, bis-acetyl acetone alkylene diimines, salicylaidehyde imine, and from metals such as beryllium, magnesium, zinc, cadmium, lead, titanium, zirconium, tin, arsenic, bismuth, chromium, molybdenum, manganese, iron, cobalt and nickel, PA1 (f) alcoholates and phenolates of metals, such as Ti(OR).sub.4, Sn(OR).sub.4, Sn(OR).sub.2 and Al(OR).sub.3, in which R is an alkyl or aryl group, PA1 (g) the salts of organic acids and of metals, such as alkali metals and alkaline earth metals, aluminum, tin, lead, manganese, cobalt, nickel and copper, for example sodium acetate, potassium laurate, calcium hexanoate, stannous acetate, stannous octoate and stannous oleate, lead octoate, manganese and cobalt napthenates, and PA1 (h) iron and cobalt metal carbonyls and organometallic derivatives of tetravalent tin, of trivalent and pentavalent arsenic, of antimony and of bismuth; particularly preferred are the salts of dialkyl tin carboxylic acids, such as dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin maleate, dilauryl tin diacetate, dioctyl tin diacetate, dibutyl tin bis (4-methylamino benzoate), dibutyl tin bis (6-methylamino caproate), trialkyl tin hydroxides, dialkyl tin oxides, dialkyl tin dialcoxides and dialkyl tin dichlorides. PA1 casting (preparation of a resin concrete), PA1 contact process (with the aid of a brush or a roller), PA1 simultaneous projection with the aid of a spray gun which is, optionally, provided with a glass cutter, PA1 filament winding. PA1 from about 25 to 50 parts by weight of at least one ethylenically unsaturated monomer, PA1 from about 50 to 75 parts by weight of an aminated unsaturated polyester resin which is the product of the reaction between (a) an unsaturated polyol polyester prepolymer and (b) a polyoxyalkylene amine, the mass ratio of (a)/(b) being at least about 0.8, and PA1 up to about 4 parts by weight of at least one cross-linking catalyst. PA1 at least one cross-linking accelerator, PA1 at least one powdery filler, and PA1 at least one fibrous reinforcing filler,
Such a material has a flexural modulus above 700 MPa and up to 1,400 MPa, and an increased resistance to heat, according to the particular measuring method described in the patent mentioned above.
In fact, the composite material described in that document has a number of disadvantages: on the one hand, the flexural modulus obtained is very low in comparison to that which may be obtained in respect of a similar material which does not contain polyoxyalkylene polyamine, as is shown in the comparative Example given below. On the other hand, when the resistance to heat of said material is determined not only by the method particular to said patent, but by the more conventional measurement of the heat distortion temperature, it is noted that said heat distortion temperature does not exceed about 50.degree. C., which is unsatisfactory for many applications of the product.
A technical problem to be overcome by the present invention is, thus, to provide a material which can be obtained in particular by the reaction-injection molding process and which combines, at one and the same time, a high flexural modulus, a high heat distortion temperature and a high impact resistance, a compromise which is not achieved by the teachings of U.S. Pat. No. 4,880,872 nor by the prior art.
On the other hand patent application FR-A-2,667,602 discloses a molding composition based on polyester-polyurethane, characterized in that it comprises a first soft phase of polyurea within a second more rigid phase of polyester-polyurethane formed by the reaction of:
wherein the ratio of the active NCO groups of the isocyanate to the NH groups of the nitrogenated compound is between about 3:1 and 100:1, the ratio of the active NCO groups to the active OH groups in the polyester-polyol is between about 0.5:1 and about 6:1, in such way that the stoichiometric index NCO: (NH+OH) is between about 0.5 and about 2.0.